Drill depth gauge



y 6, 1953 L. 1. NELSON 2,833,168

DRILL DEPTH GAUGE Filed Aug. 16, 1955 Fig.2

7 Fig.4 5 I? I9 /2 l $6 4 DRILL DEPTH GAUGE Lloyd 1. Nelson, St. Paul, Minn.

Application August 16, 1955, Serial No. 528,751

1 Claim. (Cl. 77-55) The present invention relates to new and useful improvements in gauges, particularly for hand drills, and has for its primary object to provide, in a manner as hereinafter set forth, an adjustable device of this character for accurately regulating or controlling the boring depth of the tool.

Another very important object of the invention is to provide a gauge of the aforementioned character comprising novel means for firmly securing the device in adjusted position on the tool.

Other objects of the invention are to provide an adjustable drill gauge or stop of the character described which will be comparatively simple in construction, durable, compact, light in weight and which may be manufactured at low cost.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure 1 is an elevational View, showing a gauge constructed in accordance with the present invention mounted on a drill;

Figure 2 is a perspective view of the device, showing the parts separated;

Figure 3 is a View in horizontal section through the device, taken substantially on the line 3-3 of Figure 1; and

Figure 4 is a vertical sectional view taken substantially on the line 4-4 of Figure 3.

Referring now to the drawing in detail, it will be seen that the embodiment of the invention which has been illustrated comprises a substantially cylindrical body 5 of a suitable metal or alloy. The body 5, which may be of any desired dimensions, includes a substantially tapered lower end portion 6.

Extending centrally through the body 5 is an opening or bore 7. The bore 7 is of a diameter to accommodate the drill on which the gauge is to be mounted, as indicated at 8.

Extending transversely into the body 5 at an intermediate point is a slot or kerf 9. The kerf 9 extends beyond the bore 7 and communicates therewith. The kerf 9 is for the reception of a substantially segmental removable locking plate 10 of a suitable metal or alloy. The locking plate 10 is provided with an opening 11 for alignment with the bore 7 for the passage of the drill 8. An Allen setscrew 12 is threadedly mounted in the body 5 and engaged with the locking plate 10 for binding same on the drill.

It is though that the operation or use of the device will be readily apparent from a consideration of the foregoing. Briefly, the setscrew 12 is backed off and plate 10 is inserted in the kerf 9 with the opening 11 aligned with the bore 7. The cylindrical body 5 is then slipped on the drill 8 and adjusted to the desired position. The setscrew 12 is then tightened for shifting the plate 10 in the kerf 9 for frictionally locking the gauge in adjusted position on the drill in an obvious manner. Of course, to again adjust or remove the device it is only necessary to loosen the setscrew 12. The construction and arrangement of parts, it will be observed, is such as to allow the depth gauge to be locked on the drill in positions per= mitting the finest calibrations, a highly important and desirable feature of the invention.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

A gauge for limiting drilling depth of a rotary drill comprising a body having a longtiudinally extending bore therethrough for receiving a drill, said body also having a transverse kerf defined by upper and lower walls, said kerf extending over a major portion of the area of the body and completely intersecting the periphery of the bore, a plate mounted within said kerf and having parallel upper and lower surfaces slidably engaging the walls of the kerf, said plate having an opening therethrough of substantially the same size as the bore for receiving the drill therethrough, the inner Wall of said kerf having a fiat surface extending parallel to a tangent of the bore at the nearest point on the edge of the bore, said body having a threaded aperture extending perpendicular to the inner wall of the kerf and being coaxial with a radius of the bore and extending to the periphery of the body, a setscrew threaded into said aperture and having a flat inner surface perpendicular to the longitudinal axis thereof, said plate having a flat inner face generally parallel to a tangent of the opening at the nearest point of the opening, the flat inner surface of the setscrew engaging the fiat inner surface of the plate for urging the plate diametrically of the bore for urging the opening towards misalignment with the bore for clampingly locking the body to the drill with the flat upper and lower surfaces accurately positioning the body while the opening completely encircling the drill facilitates the clamping action regardless of the orientation of the flutes on the drill and provides a wide surface of pressure against the drill.

References Cited in the file of this patent UNITED STATES PATENTS 167,884 Farmer Sept. 21, 1875 1,882,689 Albertson Oct. 18, 1932 2,280,270 Stoner Apr. 21, 1942 FOREIGN PATENTS 501,331 Great Britain Feb. 24, 1938 

